====== Activities ======
====== Terms and ideas ======
  * [[http://wiki.commres.org/wiki.php/Correlation|correlation(r)]], Pearson's correlation
    * variance
    * covariance 
    * $ r = \frac{Cov[X, Y]}{\sqrt{Var[X] Var[Y]}} $ 
    * $ r  = \frac{SP}{\sqrt{SS_{X} SS_{Y}} $ 
  * [[http://wiki.commres.org/wiki.php/Regression|regression]]
    * regression line, $ \widehat{Y} = a + bX $
    * SS of Regression vs. SS of residual, $ SS_{total} = SS_{Y} = SS_{reg} + SS_{res}$
    * R<sup>2</sup>, $ R^2 = \frac{SS_{reg}}{SS_{total}}$
    * F-test, $ F = \frac{MS_{reg}}{MS_{res}} $
  * [[http://wiki.commres.org/wiki.php/MultipleRegression|multiple regression]]